Providing lavatories on board airplanes is widely known. For examples of fixed assembly lavatories provided on board airplanes, see U.S. Pat. Nos. 5,150,863, issued Sep. 29, 1992, to Hozumi; 4,884,767, issued Dec. 5, 1989, to Shibata; 4,646,145, issued Feb. 24, 1987, to Alie, and 4,589,463, issued May 20, 1986, to Ryan. However, the opportunities of doorway space utilization are not known to Hozumi, Shibata, Alie, or Ryan.
Doorway space utilization is the idea of making use of the floor areas and spaces immediately inboard of commercial airplane exit doors not needed during night. Doorway areas and spaces are normally used only for entry and departure from the airplane while on the ground. The Federal Aviation Authority requires such areas and spaces for emergency exit and attendant assist purposes. However, during normal flight, these areas and spaces are largely unused.
By using doorway areas and spaces during routine flight, there exists an opportunity to increase seat count within an airplane. Seat count gains are the most direct way to increase a customer's perceived value of an airplane. Analysis indicates that each incremental seat added to an airplane of a given gross weight increases the value of the airplane at the time of sale by many hundreds of thousands of dollars. All things being equal, increasing seat count increases revenues, profit, and thus, perceived customer value.
Examples of apparatus providing increased space utilization on an airplane include an expandable volume lavatory disclosed in the aforementioned patent to Ryan and a convertible seat-bed disclosed in U.S. Pat. No. 3,898,704, issued Aug. 12, 1975, to Gallaher, etal. Also available for use on the McDonnell Douglas MD-11 commercial airplane is an accessible expandable lavatory for the physically impaired. When stowed, the lavatory is basically a conventionally sized module. When the need arises or on-demand, the lavatory can be expanded into the passenger doorway area to permit positioning of a wheelchair next to the toilet in the lavatory. However the McDonnell Douglas lavatory is not necessarily deployed during flight; only when there is a need to accommodate the needs of a physically impaired passenger.